[PATCH v2 03/10] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation

Lukasz Majewski
2016-10-27T06:46:30Z

The code has been rewritten to remove "generic" calls to
imx_pwm_{enable|disable|config}.

Such approach would facilitate switch to atomic PWM (a.k.a ->apply())
implementation.

Suggested-by: Stefan Agner <stefan@agner.ch>
Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
---
Changes for v2:
- Add missing clock unprepare for clk_ipg
- Enable peripheral PWM clock (clk_per)
---
drivers/pwm/pwm-imx.c | 50 ++++++++++++++++++++++++++++++++++++++------------
1 file changed, 38 insertions(+), 12 deletions(-)

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index ea3ce79..822eb5a 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -65,8 +65,6 @@ struct imx_chip {
static int imx_pwm_config_v1(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
- struct imx_chip *imx = to_imx_chip(chip);
-
/*
* The PWM subsystem allows for exact frequencies. However,
* I cannot connect a scope on my device to the PWM line and
@@ -84,26 +82,56 @@ static int imx_pwm_config_v1(struct pwm_chip *chip,
* both the prescaler (/1 .. /128) and then by CLKSEL
* (/2 .. /16).
*/
+ struct imx_chip *imx = to_imx_chip(chip);
u32 max = readl(imx->mmio_base + MX1_PWMP);
u32 p = max * duty_ns / period_ns;
+ int ret;
+
+ ret = clk_prepare_enable(imx->clk_ipg);
+ if (ret)
+ return ret;
+
writel(max - p, imx->mmio_base + MX1_PWMS);

+ clk_disable_unprepare(imx->clk_ipg);
+
return 0;
}

-static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable)
+static int imx_pwm_enable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct imx_chip *imx = to_imx_chip(chip);
+ int ret;
u32 val;

+ ret = clk_prepare_enable(imx->clk_ipg);
+ if (ret)
+ return ret;
+
+ ret = clk_prepare_enable(imx->clk_per);
+ if (ret)
+ return ret;
+
val = readl(imx->mmio_base + MX1_PWMC);
+ val |= MX1_PWMC_EN;
+ writel(val, imx->mmio_base + MX1_PWMC);

- if (enable)
- val |= MX1_PWMC_EN;
- else
- val &= ~MX1_PWMC_EN;
+ clk_disable_unprepare(imx->clk_ipg);
+
+ return 0;
+}
+
+static void imx_pwm_disable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct imx_chip *imx = to_imx_chip(chip);
+ u32 val;
+
+ val = readl(imx->mmio_base + MX1_PWMC);
+ val &= ~MX1_PWMC_EN;

writel(val, imx->mmio_base + MX1_PWMC);
+
+ clk_disable_unprepare(imx->clk_per);
}

static int imx_pwm_config_v2(struct pwm_chip *chip,
@@ -241,9 +269,9 @@ static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
}

static struct pwm_ops imx_pwm_ops_v1 = {
- .enable = imx_pwm_enable,
- .disable = imx_pwm_disable,
- .config = imx_pwm_config,
+ .enable = imx_pwm_enable_v1,
+ .disable = imx_pwm_disable_v1,
+ .config = imx_pwm_config_v1,
.owner = THIS_MODULE,
};

@@ -262,8 +290,6 @@ struct imx_pwm_data {
};

static struct imx_pwm_data imx_pwm_data_v1 = {
- .config = imx_pwm_config_v1,
- .set_enable = imx_pwm_set_enable_v1,
.pwm_ops = &imx_pwm_ops_v1,
};

--
2.1.4